uprobes: Cleanup !CONFIG_UPROBES decls, unexport xol_area

1. Don't include asm/uprobes.h unconditionally, we only need
   it if CONFIG_UPROBES.

2. Move the definition of "struct xol_area" into uprobes.c.

   Perhaps we should simply kill struct uprobes_state, it buys
   nothing.

3. Kill the dummy definition of uprobe_get_swbp_addr(), nobody
   except handle_swbp() needs it.

4. Purely cosmetic, but move the decl of uprobe_get_swbp_addr()
   up, close to other __weak helpers.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 445962a72498..51a7f535ff96 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -86,6 +86,25 @@ struct return_instance {
 };
 
 /*
+ * On a breakpoint hit, thread contests for a slot.  It frees the
+ * slot after singlestep. Currently a fixed number of slots are
+ * allocated.
+ */
+struct xol_area {
+        wait_queue_head_t       wq;             /* if all slots are busy */
+        atomic_t                slot_count;     /* number of in-use slots */
+        unsigned long           *bitmap;        /* 0 = free slot */
+        struct page             *page;
+
+        /*
+         * We keep the vma's vm_start rather than a pointer to the vma
+         * itself.  The probed process or a naughty kernel module could make
+         * the vma go away, and we must handle that reasonably gracefully.
+         */
+        unsigned long           vaddr;          /* Page(s) of instruction slots */
+};
+
+/*
  * valid_vma: Verify if the specified vma is an executable vma
  * Relax restrictions while unregistering: vm_flags might have
  * changed after breakpoint was inserted.